Nuclear units weather Hurricane Irma

FIRST PUBLISHED 4:34pm GMTUPDATE 1: 5:40pm GMT Further information from US Nuclear Regulatory Commission on current plant statusUPDATE 2: 1:45pm GMT 12 September Status of St Lucie 1 updated

Two nuclear units at St Lucie were able to continue operating as Hurricane Irma made landfall in Florida. One unit at Turkey Point was shut down as a precaution in advance of the storm as nuclear operators and regulators put storm preparation procedures into action, while the other shut down automatically because of a valve-related issue.

Turkey Point (Image: NRC/FPL)

Two Florida Power & Light (FPL) plants - Turkey Point and St Lucie - lay in the direct path of the hurricane as it approached the continental USA after causing extensive damage in the Caribbean. The company on 7 September declared an "unusual event" - the lowest of the US Nuclear Regulatory Commission (NRC) emergency classifications - at Turkey Point after the US National Weather Service issued a hurricane warning for the area, and on 9 September "conservatively" shut down one of the plant's two reactors.

As Irma's path changed, the decision was made to leave the second Turkey Point reactor online, as hurricane force winds were no longer expected at the site. Unit 4 shut down automatically on the evening of 10 September due to a "valve issue", the NRC said.

Wind and rain have diminished at the site such that Turkey Point staff exited their declaration of an "unusual event" earlier today.

No plans were put in place for closures at St Lucie, where projected wind speeds remained below the hurricane level, but the NRC on 11 September said operators were reducing power on unit 1 due to salt buildup on insulators in the switchyard that supplies offsite power. The unit was subsequently shut down, with St Lucie 2 remaining at full power.In preparation for the hurricane, staff at Turkey Point, St Lucie and other nuclear plants in the south-eastern USA worked through severe weather procedures, including ensuring that all loose debris and equipment had been removed or secured and conducting walk-downs of important systems and equipment. Preparations were verified by NRC inspectors.

The NRC dispatched additional inspectors to Turkey Point and to St. Lucie, and on 10 September the regulator activated its Region II Incident Response Center in Atlanta, Georgia. The incident response centre is now monitoring potential effects from Irma, now classed as a tropical storm, on the Hatch plant in southern Georgia and the Farley plant in southern Alabama.

As well as making preparations at its operating nuclear plants at Vogtle and Hatch, Georgia Power also put took action at the Vogtle nuclear construction site, where two AP1000 reactors are being built. In addition to walk-downs of the site to identify and secure potential hazards that could result from heavy winds, crane booms were lowered, pumps delivered to help mitigate flooding in critical areas, and weather plans put in place to ensure the safety of the site and employees, the company said.

Hurricane Irma initially made landfall in the Caribbean as a Category 5 hurricane with sustained wind speeds of more than 185 miles per hour, which made it the second-largest hurricane ever recorded. It made landfall in Florida on 10 September as a Category 4 hurricane. More than 4.6 million customers were left without power as the storm worked its way through the state.

The US National Hurricane Center said on 11 September that Irma had weakened to a tropical storm, but was still producing some wind gusts near to hurricane force. The centre of the storm was forecast to move into southern Georgia later that day, continuing into southwestern Georgia and eastern Alabama.

FPL president and CEO Eric Silagy said yesterday the company had experienced over 5 million power outages as a result of Irma, the first storm ever to impact all of its service areas across the state of Florida. A team of more than 19,000 workers is now working to restore power supplies. Researched and writtenby World Nuclear News